Guinea pig Gestation Calculator
Last updated
A guinea pig's gestation period is about 68 days, or roughly 2 months and 1 week, though it ranges from 59 to 72 days depending on breed and individual animal.
Calculate a pup due date
Estimated birthing date
Monday, 4 January 2027
Earliest
26 Dec 2026
Latest
8 Jan 2027
0 of 68 days elapsed
Milestone timeline
| Day | Milestone | Date |
|---|---|---|
| 15 | Pregnancy usually confirmable by gentle palpation or ultrasound | 12 Nov 2026 |
| 21 | Switch to unlimited alfalfa hay for extra calcium and protein | 18 Nov 2026 |
| 35 | Stop picking her up unless necessary; support the hindquarters if you must | 2 Dec 2026 |
| 45 | Pups become visible and their movement can be seen from outside | 12 Dec 2026 |
| 56 | Pelvic separation begins — check gently once a day | 23 Dec 2026 |
| 63 | Earliest normal birth; separate the boar now if he is still present | 30 Dec 2026 |
| 68 | Expected birth | 4 Jan 2027 |
How to use the guinea pig gestation calculator
- 1. Choose what you know. Enter the breeding date to get a due date, or switch to the target due date mode to work backwards to the breeding date you need.
- 2. Refine the inputs. Pick the breed so the calculator uses the right average gestation length.
- 3. Plan around the range. Use the earliest and latest dates and the milestone timeline to schedule checks, feed changes and preparation of the birthing area.
How long is a guinea pig's gestation period?
The average is 68 days from breeding to birthing, about 2 months and 1 week. Anything between 59 and 72 days is normal, and a typical litter is 2-4 pups. Treat the calculated date as the middle of that window rather than a fixed appointment.
Guinea pig gestation table: breeding date to birthing date
Breeding dates one week apart with the matching birthing date at 68 days.
| Breeding date | Expected birthing date |
|---|---|
| 28 Oct 2026 | 4 Jan 2027 |
| 4 Nov 2026 | 11 Jan 2027 |
| 11 Nov 2026 | 18 Jan 2027 |
| 18 Nov 2026 | 25 Jan 2027 |
| 25 Nov 2026 | 1 Feb 2027 |
| 2 Dec 2026 | 8 Feb 2027 |
| 9 Dec 2026 | 15 Feb 2027 |
| 16 Dec 2026 | 22 Feb 2027 |
| 23 Dec 2026 | 1 Mar 2027 |
| 30 Dec 2026 | 8 Mar 2027 |
| 6 Jan 2027 | 15 Mar 2027 |
| 13 Jan 2027 | 22 Mar 2027 |
How breed changes the birthing date
Selecting a breed swaps the average the calculator uses, which can move the birthing date by more than a week.
| Breed | Average days | Difference |
|---|---|---|
| Average | 68 | — |
| Large litter (4 or more pups) | 63 | -5 days |
| Small litter (1 to 2 pups) | 70 | +2 days |
Working backwards from a target birthing date
If you want pups on the ground in a particular week, switch the calculator to target date mode and enter the date you are aiming for. It subtracts 68 days to give the breeding date to book, plus the earliest and latest service dates that still land inside your window.